Alkylthioalkylamines represent an important class of cationic surface active agents which are used in a variety of commercial products. Alkylthioalkylamines are exemplified by the structure: EQU CH.sub.3 (CH.sub.2).sub.n --S--(CH.sub.2).sub.m --NH.sub.2
wherein n is an integer of from 4 to 17, preferably 6 to 12 and most preferably 9, and m is an integer of from 2 to 3, preferably 2. The acid addition salts of alkylthioalkylamines may also be detoxified by the present invention. A common alkylthioalkylamine is decylthioethylamine (DTEA) available from the Dow Chemical Company under the name DTEA.
Alkylthioalkylamines are utilized for a variety of commercial applications as diverse as chemical and pharmaceutical intermediates, dispersing agents, and flotation promoters as well as biocides for the treatment of aqueous systems. Aqueous systems are exemplified by once-through and recirculating cooling water systems in industrial facilities, papermaking process water, municipal water/wastewater systems, service water systems, fire protection systems, ship ballast water and cooling reservoirs. A major concern with the use of alkylthioalkylamines in aqueous systems is their release and environmental impact to aquatic ecosystems and wastewater treatment facilities. Alkylthioalkylamines are toxic to aquatic life including bacteria, algae, macroinvertebrates and fish. These compounds, if discharged in excess, could upset wastewater treatment processes. Releasing residual amounts of these compounds may cause unacceptable short term or long term impact to aquatic life within the receiving system. Aquatic life referred to herein includes microbiological organisms (i.e., bacteria, fungi, and algae), fish, plankton and benthic macroinvertebrates and zooplankton assemblages living within streams, rivers, lakes, reservoirs, estuaries and oceans.
Concerns with respect to such discharge of alkylthioalkylamines and other toxic waste products into the aquatic environment has grown significantly in recent years. This growing concern is manifested, in part, in the actions of municipal, state and federal environmental regulatory authorities who have either already enacted legislation to eliminate the pollution of our natural water or who are in the process of promulgating such regulations. The regulations and legislation enacted by such authorities are becoming more and more stringent with the ultimate goal being the prohibition of the addition of any chemical compound into the aquatic environment which has even an insignificant effect on the aquatic life which exists therein.
In response to such legislation, industrial users of large volumes of water have sought out methods of decreasing effluent toxicity. For example, U.S. Pat. No. 3,524,812 teaches a method of decreasing the biocidal effects of bromonitrostyrene by reaction with a compound selected from a water soluble sulfite compound, hydrogen peroxide, and potassium permanganate. U.S. Pat. No. 4,204,954 teaches the use of anionic substances such as sodium stearate, sodium dodecylsulfate, dodecylglycine, dodecylaminoethylglycine, sodium palmitate, sodium oleate, sodium linolate, and sodium dioctylsulfosuccinate to detoxify quaternary ammonium based biocides. U.S. Pat. No. 5,030,358 discloses the deactivation of organophosphorous biocides in systems which also contain dissolved oxygen by adding a catalytic amount of activated carbon. U.S. Pat. No. 5,169,536 teaches a method of detoxifying cationic surfactant based biocides, such as quaternary ammonium based biocides, with a combination of bentonite clay detoxification agent and a polymerized alkylnaphthalene sulfonate sodium salt dispersing agent.